Little Rock police turned the package over to the county coroner, who questions where they came from and if they were properly obtained.

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"We've come to the conclusion that there is a black market out there for human body parts for research or for whatever reason," said Pulaski County coroner Garland Camper. "We just want to make sure these specimens here aren't a part of that black market and underground trade."

The heads were being transported to the Fort Worth office of Medtronic, a leading medical research and technology company based in Minnesota.

Medtronic spokesman Brian Henry said it is common to ship body parts for medical education and research, but he said it is rare for a shipment to be seized.

But Henry said they were "four full cranial specimens and 40 pairs of temporal bone ear blocks."

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He identified the supplier as JLS Consulting of Wynne, Ark.

JLS's business license was revoked in December, according to the Arkansas Secretary of State's online database.

Company founder Janice Hepler did not return phone calls Wednesday. Her voice mail indicated it was full and no longer accepting messages.

But in an earlier interview with the Arkansas Democrat-Gazette, she blamed the problem on the private courier she had hired to transport the body parts.

"Nothing is wrong," the newspaper quoted her as saying. "We're providing the documentation."

But the coroner said the paperwork has "discrepancies."

Federal law generally prohibits the sale of human body parts, although suppliers can be reimbursed for expenses in cases of legitimate medical education or research.

"It is a lucrative business. There is money to be made," Camper said. "We're hoping that this isn't the case."

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